how many combinations ?

Hello
Can someone tell me how can i calculate combinations of 2 numbers on x times repeating.
so for example on 1 and 2 on repeating 8 times.
for example:
1 one is: 1 1 1 1 1 1 1 1
2 one is: 1 1 1 1 1 1 1 2
3 one is: 1 1 1 1 1 1 2 2
…
… and so on …
…
and is there any website who calculated this for you and give all this numbers too.
so, if possible if i can get all different combinations writen down in excele for example.
and mabye on 9 times too how many combinations is with 2 numbers (1 and 2)
tnx,
regards
Answer #1
You calculate the combinations via the power of two if I’m not mistaken, there are 2^8=256 combinations for this problem, but I don’t know how you can calculate it.
Answer #2
Put the three numbers into an excel spreadsheet (each number in an individual box going downwards). Then select the three of them and expand the box downwards further and excel will continue the pattern. edit.. maybe not..
Just tried it, and didnt work, properly. This method would work, but your have to format the cells and am not sure which format settings would be needed for the above info…
Answer #3
There are two ways to fill the first place (either a 1 or a 2), two ways to fill the second place, etc. Since there are 8 places, there are 28=256 possible combinations.
In general, if there are n repititions, then there are 2n possible combinations.